应用表面光电压谱研究固体表面酸度

A Study of Solid Surface Acid by Surface Photovoltage Spectrometry

测量与亚带隙辐射相关的表面光电压谱可极其灵敏地得到固体表面态信息。固体表面酸与受体表面态相关。本文用近红外光辐射测试了分子筛和杂多酸的表面光电压,观察到在900～1500 nm光谱区有表面光电压响应。不同的峰位对应不同受体表面态位置,代表不同酸的强度;峰强度对应态密度,反映了酸总量。对初步结果也进行了理论分析。

The information of solid surface states can be obtained sensitively by measuring the surface photovoltage relating to the sub-bandgap transition. And a solid surface acid is related to the acceptor type surface states. In this paper, the surface photovoltage spectra of some zeolites and heteropolyacids were measured by sub-bandgap light. Is is found that there are acceptor type surface states at 900-1500 nm. The peak position corresponds to the energy level position of the surface states representing their acid strength; the peak strength corresponds to the surface state density indicating their acid amount. Finally, the experiment results are discussed theoretically.